The resistance against Listeria monocytogenes and the formation of germinal centers depend on a functional death domain of the 55 kDa tumor necrosis factor receptor

The biological functions mediated by the death domain of the 55-kDa tumor n ecrosis factor receptor (TNFRp55) in vivo are still elusive. TNFRp55 mutant s lacking a functional death domain were expressed in TNFRp55(-/-) and in T NFRp55(+/-) mice as transgenes under control of the H-2K(b) promoter. Analy sis of these animals revealed that signals originating from the TNFRp55 dea th domain are indispensable for the protection against Listeria monocytogen es, the expression of mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in the spleen and the development of splenic germinal centers. Furthermore , the transgenic coexpression of the TNFRp55 mutants in TNFRp55C(+/-) mice exerts a dominant negative effect on the signaling of the endogenous recept or chains in vivo.